Please check whether he is teething. When a child has teeth, his gums will itch. If the child really can't help it, bite something to stop itching. If he is teething, please buy a grinding stick for his child, and pay attention to supplementing calcium to promote the rapid growth of his teeth.
Personality and psychological problems, when it comes to this question, parents should think for themselves, whether they often play with their children, chat with them, take them out shopping, meet strange children and teach them things they don't understand. If you are busy and neglect your child's psychological growth and emotional growth, children will seek comfort if they feel lonely, but there are few ways for children to seek comfort. They don't want adults to go out and get drunk, or find someone to tell them that they can hold a toy tightly or do something repeatedly to transfer their inner loneliness. You should observe whether your child is cheerful, likes to ask questions and likes to communicate with others. Five-year-olds should be naughty, lively and naive, and prefer to ask questions. Please don't be angry if you have certain personality and psychological obstacles. The child is too young to know anything and know nothing. We should love them more and guide them, not just provide them with food and clothes. That's no different from keeping a cat and a dog. My daughter is a little over 4 years old. She has the same personality and the same way of speaking as an adult. Sometimes she teaches better than us. She likes to jump around all day. Don't worry about her wild child. Fertility is nature, and nature is the right nature.
If your child has no personality and psychological barriers, I have remedies. You can try. Give him bitter gourd and lemon. Doesn't he like to bite? Give him a bite of that terrible food, just like when we were weaned. Mom put pot ashes on her nipples and we went to eat. It's so bitter that we don't want to eat milk, and the milk is bad.
If none of the above problems can alleviate your child's habits, I suggest you see a doctor. After all, the child is our future. He is still young and can be corrected. And to be honest, it's really bad to have this habit at the age of five. Think about it. You must use a pen and an eraser at school in the future. It's dangerous to bite.
Finally, I wish the children have corrected and grow up happily and healthily every day!